Control of di/dt and dv/dt in a MOS-gated transistor by gate current adjustment

摘要

To turn on a Mos-gated transistor, such as an inductively-loaded MOSFET 418 or IGBT in a converter, a current generator 411 coupled to the gate of the transistor 418 is enabled to generate a first current in dependence on a first resistor 413 and is subsequently enabled to generate a second current in dependence on a second resistor 414. Switchover 412 between these two gate currents is made when the transistor drain-source voltage begins to fall, indicating transition from the current-change phase to the voltage change phase of the switching sequence (figure 1B). The turn-off sequence is similar (figure 1C). Closed-loop control of the voltage and current slopes may be provided; the voltage slope may be sensed by a capacitor 417 connected to the transistor drain, while the current slope may be sensed by the inductive reactance of a bond wire (figure 6).